1. Field of the Invention
The invention relates to the separation of sheet groups from the bottom of a stack; for example, in advance of a punching station for forming perforations in the edges of booklet sheets for the reception of wire hinges.
2. Description of the Prior Art
My U.S. Pat. No. 3,452,628 issued July 1, 1969, shows a hole punching machine for paper sheets which incorporates a sheet group separating mechanism of the type with which the present invention is concerned. This mechanism utilizes one or more rotating slotted disks on which the sheet stack rests. A finger adjacent the lower portion of the stack at one corner enters to separate a group of sheets, and a depressor depresses the corner so that it will pass into a disk slot. Continued rotation of the disk results in a group of sheets passing beneath the disks to a conveyor.
A problem arises on occasion with respect to such equipment if ambient conditions are such that the paper edges tend to curl, pull up and contract. In this case, the finger and/or the depressor may only partially engage or entirely miss the proper position on the stack so that only a portion of the sheet group, or none at all, will drop down below the disks.